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Updated: Nov 12, 2025
Author Spotlight: Advancements in Understanding and Combatting Shigella Infections
Published on: February 9, 2024
Diarrhea in an infant due to Shigella flexneri 1 carrying multiple cephalosporinase-encoding genes
M John Albert1, Prashant Purohit2, Laurent Poirel3,4,5
1Department of Microbiology, Faculty of Medicine, Kuwait University, Jabriya, Kuwait. manuel.albert@ku.edu.kw.
Background:
Infections caused by multidrug-resistant shigellae resistant to broad-spectrum cephalosporins are becoming more prevalent in the Middle East. We report a case of severe diarrhea due to a multiresistant Shigella flexneri 1 strain carrying four different ß-lactamase genes.
Case Presentation:
A one-year-old Syrian infant presented with severe acute diarrhea, vomiting and dehydration. She did not respond to empirical treatment with amoxicillin-clavulanic acid followed by cefotaxime. Later, stool culture revealed S. flexneri 1 resistant to both these drugs. The patient was successfully treated with meropenem to which S. flexneri 1 was susceptible. The isolate was resistant to eight classes of antibiotics, and the whole genome sequence (WGS) identified four ß-lactamase genes (blaCTX-M-15, blaEC-8, blaOXA-1, and blaTEM-1) along with genes mediating resistance to seven other antibiotic classes. The WGS also identified several virulence genes including senA that encodes ShET-2 which induces watery diarrhea. Phylogenetically, the isolate was closely related to isolates from South Asia.
Conclusions:
This report highlights the emergence of extremely resistant Shigella that has acquired multiple resistance genes to cephalosporins rendering these drugs ineffective.
Insights
Multidrug-resistant Shigella flexneri 1 infections are rising in the Middle East. A severe case in an infant highlighted resistance to cephalosporins due to multiple beta-lactamase genes, necessitating alternative treatments.
Area of Science:
- Microbiology
- Infectious Diseases
- Genomics
Background:
- Rising prevalence of multidrug-resistant Shigella in the Middle East.
- Shigella strains resistant to broad-spectrum cephalosporins pose a significant public health threat.
- Emergence of Shigella strains with extensive antibiotic resistance patterns.
Purpose of the Study:
- To report a case of severe diarrhea caused by a multidrug-resistant Shigella flexneri 1 strain.
- To characterize the antibiotic resistance profile and genetic makeup of the isolate.
- To highlight the clinical implications of emerging cephalosporin-resistant Shigella infections.
Main Methods:
- Clinical case presentation of a pediatric patient with severe diarrhea and dehydration.
- Antimicrobial susceptibility testing of the Shigella isolate.
- Whole genome sequencing (WGS) to identify resistance and virulence genes.
- Phylogenetic analysis to determine isolate relatedness.
Main Results:
- The Shigella flexneri 1 isolate exhibited resistance to eight antibiotic classes, including broad-spectrum cephalosporins.
- WGS identified four beta-lactamase genes (blaCTX-M-15, blaEC-8, blaOXA-1, and blaTEM-1) and other resistance genes.
- The isolate carried virulence genes, including senA, contributing to severe watery diarrhea.
- The patient was successfully treated with meropenem.
Conclusions:
- Extremely resistant Shigella strains are emerging, acquiring multiple resistance genes.
- Cephalosporin-based treatments are becoming ineffective against these resistant strains.
- This case underscores the need for continuous surveillance and development of alternative therapeutic strategies.
